RNA-PROTEIN CONDENSATION PATTERNS THE CYTOSOLIC LANDSCAPE OF A SYNCYTIUM

To function properly and survive in differing environmental conditions, every cell must organize their cytoplasm in one form or another. This requirement is increasingly necessary in large, multinucleated cells. Traditionally, this has been thought to be mainly driven by membrane-bound compartments (i.e. organelles) that help eukaryotic life organize into distinct biochemical spaces. More recently, it’s become apparent that the continuous cytosol is also organized into distinct compartments, through entirely separate means. In the multinucleated Drosophila embryo, approximately 70% of mRNA transcripts were determined to be heterogeneously localized across the cell, and mRNA spatial organization in the multinucleate fungus Ashbya gossypii has implicated phase separating RNA binding proteins (RBPs), where transcript heterogeneity is critical for autonomous nuclear division and polarized growth in these syncytial cells. The ability of RNAs to condense into droplets is in many instances contributing to previously appreciated mRNA localization phenomena. Phase separation enables mRNAs to selectively and efficiently co-localize and be co-regulated allowing control of gene expression in time and space. The work presented here demonstrates that mRNA sequence not only drives the localized condensation of RNA-protein droplets in A. gossypii, but also, governs the identity of these specialized RNA granules. Work in this thesis provides evidence that the RNA binding protein, Whi3, exhibits differential phase-separation behavior depending on which RNA target it binds and that this differential behavior is specified by features within the mRNA sequence. In addition, this work investigates the possibility of an auto feedback mechanism by which Whi3 phase separates with its own mRNA to drive differential crowding within the cytosol to promote droplet condensation in crowded cytosolic regions, thus creating individual territories of cytosol within a common syncytial cytoplasm. These data suggest mechanisms by which cells can employ asymmetric RNA localization, specifically the localization of RNAs via phase-separating RNA binding proteins, to generate functionally distinct domains to achieve efficient, and timely cytosolic organization.Doctor of Philosoph

Realising potential and recognising paradox: The national induction and mentoring project

Although comprehensive policy and resourcing of beginning teacher induction and mentoring can improve teacher retention and quality, there is growing recognition that combining on-site leadership and policy is integral to providing effective learning for teachers. This has led to an increased interest in melding policy and resources with school and service leadership to promote consistency of beginning teachers’ induction and mentoring experiences. This article describes and provides insights into a project involving four pilots which are trialling the draft national guidelines for effective induction programmes and mentor teacher development. An external evaluation across the four pilots has revealed that national guidelines can be a positive lever for effecting change in induction and mentoring practices. Implementing such change nationally will require leaders to take seriously an educative, transformative approach to learning for both beginning teachers and their mentors

Realising potential and recognising paradox: The national induction and mentoring project

Although comprehensive policy and resourcing of beginning teacher induction and mentoring can improve teacher retention and quality, there is growing recognition that combining on-site leadership and policy is integral to providing effective learning for teachers. This has led to an increased interest in melding policy and resources with school and service leadership to promote consistency of beginning teachers’ induction and mentoring experiences. This article describes and provides insights into a project involving four pilots which are trialling the draft national guidelines for effective induction programmes and mentor teacher development. An external evaluation across the four pilots has revealed that national guidelines can be a positive lever for effecting change in induction and mentoring practices. Implementing such change nationally will require leaders to take seriously an educative, transformative approach to learning for both beginning teachers and their mentors

The Histone Methyltransferase SUV39H1 Suppresses Embryonal Rhabdomyosarcoma Formation in Zebrafish

Epigenetics, or the reversible and heritable marks of gene regulation not including DNA sequence, encompasses chromatin modifications on both the DNA and histones and is as important as the DNA sequence itself. Chromatin-modifying factors are playing an increasingly important role in tumorigenesis, particularly among pediatric rhabdomyosarcomas (RMS), revealing potential novel therapeutic targets. We performed an overexpression screen of chromatin-modifying factors in a KRASG12D-driven zebrafish model for RMS. Here, we describe the identification of a histone H3 lysine 9 histone methyltransferase, SUV39H1, as a suppressor of embryonal RMS formation in zebrafish. This suppression is specific to the histone methyltransferase activity of SUV39H1, as point mutations in the SET domain lacked the effect. SUV39H1-overexpressing and control tumors have a similar proliferation rate, muscle differentiation state, and tumor growth rate. Strikingly, SUV39H1-overexpressing fish initiate fewer tumors, which results in the observed suppressive phenotype. We demonstrate that the delayed tumor onset occurs between 5 and 7 days post fertilization. Gene expression profiling at these stages revealed that in the context of KRASG12D overexpression, SUV39H1 may suppress cell cycle progression. Our studies provide evidence for the role of SUV39H1 as a tumor suppressor

Spatial heterogeneity of the cytosol revealed by machine learning-based 3D particle tracking

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in McLaughlin, G. A., Langdon, E. M., Crutchley, J. M., Holt, L. J., Forest, M. G., Newby, J. M., & Gladfelter, A. S. (2020). Spatial heterogeneity of the cytosol revealed by machine learning-based 3D particle tracking. Molecular Biology of the Cell, 31(14), 1498-1511, doi:10.1091/mbc.E20-03-0210.The spatial structure and physical properties of the cytosol are not well understood. Measurements of the material state of the cytosol are challenging due to its spatial and temporal heterogeneity. Recent development of genetically encoded multimeric nanoparticles (GEMs) has opened up study of the cytosol at the length scales of multiprotein complexes (20-60 nm). We developed an image analysis pipeline for 3D imaging of GEMs in the context of large, multinucleate fungi where there is evidence of functional compartmentalization of the cytosol for both the nuclear division cycle and branching. We applied a neural network to track particles in 3D and then created quantitative visualizations of spatially varying diffusivity. Using this pipeline to analyze spatial diffusivity patterns, we found that there is substantial variability in the properties of the cytosol. We detected zones where GEMs display especially low diffusivity at hyphal tips and near some nuclei, showing that the physical state of the cytosol varies spatially within a single cell. Additionally, we observed significant cell-to-cell variability in the average diffusivity of GEMs. Thus, the physical properties of the cytosol vary substantially in time and space and can be a source of heterogeneity within individual cells and across populations.We would like to thank the 2016 Physiology course and Christina Termini at the Marine Biological Laboratory in Woods Hole, MA, Gregory Brittingham, and Marcus Roper for initial experiments and perspectives on pipeline. We thank David Adalsteinsson for help with DataTank software and many conversations about image analysis on large datasets. We thank Emmanual Levy (Weizmann Institute) for providing plasmids encoding synthetic phase separating peptides. This work was supported by Google Cloud, the National Science Foundation (NSF), the National Institutes of Health (NIH), and the Natural Sciences and Engineering Research Council of Canada (NSERC). ASG, EML, and GAM were supported by the NSF (RoLs: 1840273), HHMI faculty scholar award and the NIH (R01GM081506). JMN was supported by the NSERC (RGPIN-2019-06435, RGPAS-2019-00014, DGECR-2019-00321) and the NSF (DMS-171474). MGF was supported by the NSF (DMS-1816630, DMS-1664645). LJH was supported by the NIH (R01GM132447)

The Grizzly, November 16, 2006

Election Results Bring Significant Changes • Ursinus Maintains its Health • Peace Vigil on Campus • Lecture Examines the Ethical Treatment of Abandoned Embryos • SquadZilla Brings Hip-Hop to Life at Ursinus • Ursinus Campaign Surpasses Goal • HPV and Cervical Cancer: The Facts, Part II • Preview of the Upcoming UCDC Performance • The Labyrinth: Not Just David Bowie in Spandex • Review of The Sisters Rosensweig • Opinions: Nerf: Yardstick of the Pentagon; American Press Needs Revamping • Bears Down Dickinson in Battle of Top Teams in Centennial Conference • Bears Win Third Straight CC Championship!https://digitalcommons.ursinus.edu/grizzlynews/1725/thumbnail.jp

The Grizzly, November 2, 2006

Escape Velocity Dancers Light Up the Stage in the Black Box Theater • Letter to the Editor • Drive to Support the Troops a Success • Ursinus Homecoming 2006: There\u27s No Place Like Home • Blood Drive a Success on Campus • Batteries Included • A Look at Muslim Women in History: Professor Barbara R. von Schlegell Speaks • UC\u27s Opportunity to Support American Troops • Haunting Tales from Main Street • 2008 Preview: Part I • Opinions: Iraq: Should We Stay or Should We Go? • Football Pounds Hopkins on Homecoming • One Win and In for Women\u27s Soccer • Homecoming Victory for Field Hockeyhttps://digitalcommons.ursinus.edu/grizzlynews/1723/thumbnail.jp

The Grizzly, October 26, 2006

Editorial: Putting the Pieces Back Together • Possible Scam Raises Concerns • Town Hall Meeting Brings Forth Campus Issues • Food Drive a Success • Fall is in the Air • Story Behind the Statue: Praha • Get to Know the Nominees • Opinions: Long Live Noise; Swept Under the Rug; Truth About Study Abroad • Women\u27s Volleyball Swept by Gettysburg • Bullets Offense Too Much for Bears • Bears Make Run for Playoffshttps://digitalcommons.ursinus.edu/grizzlynews/1722/thumbnail.jp

The Grizzly, March 1, 2007

Media Lecture: The Jailhouse Doesn\u27t Rock • Peanut Butter Recall Update • Annual UC Job and Internship Fair • Living in Sin • Creating Communication Elation • Spotlight on Coach Kevin Small • Laramie Hits Big at Ursinus • Nutrition Tips: Fad Diets • Opinions: English as the Official Language? • Bears Capture Centennial Conference Title • Men\u27s Lacrosse Season Previewhttps://digitalcommons.ursinus.edu/grizzlynews/1733/thumbnail.jp

The Grizzly, November 30, 2006

Alcohol Awareness on the Front Burner of the Ursinus Campus • Diversity Forum Held for Staff and Students • 2nd Annual Relay for Life Officially Kicked Off at Ursinus • Town Hall Discusses Incidents on Campus • An Oral Examination • UCDC Performs Superbly in Latest Show • People Seeing People: The Artwork of Seward Johnson • Highlights of the Exposure Week Events and Festivities • Opinions: The Meaning of Liberal Arts; Racism in Our World and Home • Ursinus 2006 Division III Field Hockey National Champions! • Swimming to Successhttps://digitalcommons.ursinus.edu/grizzlynews/1726/thumbnail.jp